In chemico evaluation of skin metabolism: Investigation of eugenol and isoeugenol by electrochemistry coupled to liquid chromatography and mass spectrometry.

Skin sensitization is initiated by the modification of proteins located in the skin. After oxidative activation, eugenol and isoeugenol have the potential to modify skin proteins and therefore cause sensitization processes. Despite their known skin sensitizing properties, they are of common use in cosmetic products.

Combination of electrochemistry and nuclear magnetic resonance spectroscopy for metabolism studies.

During the development of new materials demonstrating biological activity, prediction and identification of reactive intermediates generated in the course of drug metabolism in the human liver is of great importance. We present a rapid and purely instrumental method for the structure elucidation of possible phase I metabolites. With electrochemical (EC) conversion adopting the oxidative function of liver-inherent enzymes and nuclear magnetic resonance (NMR) spectroscopy enabling structure elucidation, comprehensive knowledge on potential metabolites can be gained.

Electrochemistry/mass spectrometry as a tool in the investigation of the potent skin sensitizer p-phenylenediamine and its reactivity toward nucleophiles.

Rationale: Although para-phenylenediamine (PPD) is known to cause severe allergic contact dermatitis in consequence of autoxidation and/or skin metabolism pathways, it is commonly utilized as an ingredient in permanent hair dyes. The aim of this work was to simultaneously accelerate the autoxidation process and to simulate the metabolic activation of PPD using a purely instrumental system.

Methods: Electrochemistry (EC) in combination with electrospray ionization mass spectrometry (ESI-MS) was used in this study to assess the skin-sensitizing potential of PPD.

Electrochemistry/liquid chromatography/mass spectrometry to demonstrate irreversible binding of the skin allergen p-phenylenediamine to proteins.

Rationale: para-Phenylenediamine (PPD) is a potent and well-known allergen, which is commonly used in hair or fur dyes and can cause severe allergic contact dermatitis. In this work, the skin-sensitizing potential of PPD with respect to the conjugation of proteins was evaluated using an approach without animal testing.

Methods: Electrochemistry (EC) coupled offline to liquid chromatography (LC) and electrospray ionization mass spectrometry (ESI-MS) was employed to convert the pre-hapten PPD into its reactive hapten analogs.

Electrochemical oxidation and protein adduct formation of aniline: a liquid chromatography/mass spectrometry study.

Historically, skin sensitization tests are typically based on in vivo animal tests. However, for substances used in cosmetic products, these tests have to be replaced according to the European Commission regulation no. 1223/2009.